The present invention relates to retarding mold growth on partially baked pizza crusts intended to be stored at ambient or refrigerated temperatures in either sealed or unsealed packages.
Pizza is a popular item in restaurants and pizzerias. These places, however, most often lack the facilities and/or labor for making the pizza crusts because they must be rolled out and prebaked before application of sauce and topping materials. For this reason, pizza crusts are often purchased from large manufacturers of crusts, partially baked, and the restaurants and the pizzerias subsequently apply sauce and topping materials, and then bake shortly before serving to the customer.
The crust manufacturers make partially baked pizza crusts in large volume, and then ship them to distributors, often over considerable distances, even by transcontinental shipping. The distributors then deliver the crusts to the restaurants and pizzerias. The partially baked pizza crusts are stored under refrigeration, both during shipping and in the restaurant prior to use, where the amount of refrigerated storage space is often severely limited.
Partially baked pizza crusts are subject to mold and yeast growth without continued refrigeration as a result of contamination by spores of mold and yeast contained in the atmosphere. Contamination can, and usually does, occur within the short time between the normal partial baking and packaging steps in the crust manufacturing process. Mold growth begins to appear within five to seven days after preparation of the partially baked pizza crusts, if kept unrefrigerated and at ambient or room temperatures, typically 70.degree. to 80.degree. F. Mold growth on the pizza crust renders it unsuitable for human consumption and means that the product must be destroyed.
While refrigeration retards mold and yeast growth, it is expensive and is not always convenient. Moreover, if refrigeration is lost, the pizza shells are susceptible to attack.
Hermetically sealed containers have been long recognized as a means for reducing the mold and yeast growth. However, hermetically sealed containers are expensive and impracticable. Moreover, when the seal is broken, as when the first pizza crust is removed, the remaining partially baked crusts in the package are exposed to atmospheric mold and yeast spores.
One current practice for handling and storing partially baked crust is to stack the crusts in a ventilated polyethylene bag, for example, in stacks containing about two dozen crusts, which are then placed in corrugated shipping containers. The entire package is then refrigerated at temperatures of 32.degree. F to 40.degree. F. However, even under these low temperatures (32.degree. F to 40.degree. F), the crusts may mold within 3 to 4 weeks.
It is highly desirable that the partially baked pizza crusts remain mold-free for a period of about eight weeks or longer, in order to allow time for shipping, inventory, and storage prior to use. For this reason, the current practice is to incorporate calcium propionate into the dough mix, after which the crusts are refrigerated (32.degree. - 40.degree. F). However, mold growth with propionate treated crusts will appear in 3 to 5 weeks, even when refrigerated. The mold growth with propionate treated crusts will appear in 3 to 7 days, if non-refrigerated and maintained at ambient temperatures.
Various known preservatives commonly applied in the baking and food industry (for example, sodium propionate) have been used within legal and normally acceptable limits in efforts to extend the refrigerated shelf life of partially baked pizza crusts, but have met with only limited success.
Although mold and yeast growth are ordinarily referred to collectively, the spoilage in partially baked pizza crusts is due primarily to germination of mold spores.
Ethyl alcohol has been used an an anti-bacterial agent in and for certain foods. It has also been taught as being useful in controlling the germination of mold spores in certain kinds of perishable foods in conjunction with hermetically sealed packages and usually in conjunction with continuous refrigeration. However, ethyl alcohol has not been taught as being useful for retarding and preventing the germination of mold spores in partially baked food products, such as pizza crusts, especially where non-refrigerated, ambient temperature storage conditions are employed or when unsealed packaging materials are used.